Laser apparatus, widely used by surgeons for ablating or cutting tissue, generally includes a handpiece assembly manually-graspable by the surgeon for directing the laser beam to preselected working areas via an optical fiber at the distal end of the handpiece. The optical fiber is frequently enclosed within a bendable sheath which may be bent by the surgeon to a desired configuration according to the preselected working area to receive the laser energy. A serious problem in such handpieces, however, is that optical fibers are highly sensitive to stress fracture; that is, they are easily breakable if bent too sharply.
One way of solving this problem is to provide the apparatus with a plurality of interchangeable handpieces each having a desired curvature, enabling the surgeon to select the appropriate curved handpiece according to the configuration desired for a preselected working area. This solution, however, is very expensive since it requires a separate handpiece for each curvature. Moreover, it is also relatively inconvenient to the surgeon, since it may require realignment of the optical fiber in the handpiece with the laser beam delivery system at the proximal end of the handpiece for each removal of one handpiece and attachment of another in its stead.
A further drawback to this solution is the fact that stress fracture depends not only on the curvature forced on the fiber, but also on the time for which the fiber is forced to assume the curvature; therefore, holding the fiber at a particular curvature for a long period of time reduces the tightness of the curvature that the fiber is capable of assuming before stress fracture may occur.